This invention is concerned with a method of inhibiting the formation of dental plaque which employs certain surfactants and oral compositions containing such surfactants.
Dental plaque is a dense, heterogeneous, non-calcified bacterial mass which firmly adheres to the tooth surface to the degree that it resists wash off by salivary flow. The bacteria contained in plaque possess varying degrees of pathogenic activity and are responsible in part for dental caries, gingivitis, mouth odor and periodontal disease. Streptococcus mutans is one of the bacteria found in dental plaque and it has been found to possess a high cariogenic potential in a variety of laboratory animals. Actinomyces viscosus, another dental plaque bacteria, has been associated with gingivitis and root surface caries. Obviously the removal or inhibition of plaque formation would significantly reduce the occurences of these diseases.
Plaque is generally removed by employing mechanical cleaning using an abrasive dentifrice, by flossing or by rinsing with an antibacterial (anti-plaque) mouthrinse. However, plaque deposited between teeth is difficult to remove by mechanical cleaning and flossing does not remove plaque located at the gingival margin. Anti-plaque mouthrinses serve as an adjunct to mechanical plaque removal. To date, an anti-plaque mouthrinse that can take the place of mechanical plaque removal has not been discovered. Mouthrinses are often ineffective at the later stages of plaque development and are useless if the plaque has become calcified to form calculus or tartar.
Plaque formation on a clean tooth, it is generally believed, starts with the formation of a pellicle or cuticle composed of salivary constituents. The pellicle is an amorphous, membranous layer which covers the enamel surface and is considered to consist of salivary glycoproteins, polypeptides and other salivary constituents which have become selectively adsorbed on the tooth surface. The pellicle is usually free of bacteria. The pellicle is formed within minutes after the tooth is cleaned and the adsorbed materials eventually become transformed into a highly insoluble coating. Thereafter an initial adherence of bacterial occurs on the acquired pellicle. Thereafter bacteria produce extracellular polysaccharides (called glucans) from sucrose catalyzed by the enzyme glucosyl transferase which aid entrapment and adherence of other bacteria.
The cariogenic potential of S. mutans for example, is associated with its ability to form dental plaque and this ability is dependent upon the synthesis of extracellular polysaccharides from sucrose.
In addition to initial adherence and glucosyltransferase catalysis which aids adherence the coaggregation of varous species of bacteria occurs in which specific bacteria attach to each other by synthesizing polymers which bind similar and dissimilar cells together although there are some species that will not coaggregate.
In an effort to rid teeth of plaque the prior art has described agents incorporated into oral preparations such as dentifrices which inhibit the formation of plaque rather than its removal as described above.
In U.S. Pat. No. 4,117,107 for example, a method for retarding pellicle and plaque formation is described which includes contacting sites of plaque formation and growth with a dental preparation containing certain fatty acid amido betaines.
Similarly, U.S. Pat. No. 4,130,637 provides betaine compounds derived from higher alkyl dimethyl carboxylic acid quarternary ammonium compounds effective in controlling dental plaque without producing an esthetically unacceptable discoloration of the teeth.
U.S. Pat. No. 4,360,515 provides compounds for the prevention of attachment of dental plaque to the teeth comprising certain sulfonated alkoxynaphthalenes and the pharmaceutically acceptable salts thereof.
U.S. Pat. No. 4,619,825 describes a plaqueinhibiting composition comprising an aqueous dispersion of emulsan which can be incorporated in dental preparation toothpastes or mouthwashes.
U.S. Pat. No. 3,981,989 deals with an oral preparation for the prevention of tooth decay containing dextranase stabilized with a special protein such as gelatin or peptone. Nonionic surfactants may also be added with an anionic surfactant to impart stability to the dextranase. Sodium acyltaurate is a suitable anionic surfactant and is preferably present to the extent of 0.5% to 5% by weight of the oral preparation.
British Patent Specification No. 990,957 describes a strontium ion-containing toothpaste for treatment of hypersensitive dentin whch contains, inter alia, compatible surface-active foaming agents including fatty-acid N-methyl taurine condensates.
The present invention, on the other hand, provides an effective plaque inhibiting composition containing certain classes of surfactants which act to prevent the initial adherence of bacteria and the formation of extracellular polysaccharides from bacteria which are catalysed by glucosyl transferase in the formation of plaque and therefor substantially inhibit its formation. The surfactants are effective in very low concentrations and are suitable for use in oral compositions.